This proposal describes a prospective double blind randomized trial to evaluate the effectiveness of aerosolized cyclosporine (ACsA) as prevention of acute rejection after lung transplantation. Patients with recurrent acute rejection commonly develop chronic rejection characterized histologically by obliterative bronchiolitis and an inexorable decline in lung function. Cyclosporine targeted directly into the lung allograft by aerosol inhalation may offer important advantages over systemic immunosuppressive therapy.